Development Of The Triggering System Based On Pulse Transformer

SG-III energy module functioning as a high power laser source, supplying pumpingenergy for Xenon (Xe) flashlamps, is one of the most important devices of a large laserfacility. A two-electrode graphite spark gap switch is used as the main discharge switch andtriggered by a high voltage nanosecond pulse generator. The operation characteristics of thetwo-electrode graphite spark gap switch will have impact on the SG-III’s performance.These characteristics are determined by the switch itself and the quality of the trigger pulse.According to the requirements of SG-III for the triggering system, a trigger generatorbased on pulse transformer is designed and constructed. In this thesis, the design anddevelopment of the pulse transformer with a closed magnetic core are described, includingthe selection of magnetic material, core type, winding type, insulation type, etc. Theleakage inductance of the pulse transformer is presented based on comparison of theexperimental results and the theoretical analysis. A pulse transformer with a load of0.48nF,output voltage of more than148kV, rise time of5.80μs and winding ratio of65is obtainedand presented.The other key components of the triggering system are selected or designed in thisthesis, including the peaking gap switch, the primary discharge switch, diode, etc. Thelayout and structure of the trigger system are designed to satisfy the requirements forelectrical insulation and mechanical connection. It’s very convenient to assemble,disassemble and maintain the triggering system.The trigger characteristics of the two-electrode spark gap switch are tested with thetriggering system. When compared with a conventional2-electrode peaking gap switch, thenovel peaking gap switch has both a more stable impulse breakdown voltage and lowerjitter. The impulse breakdown characteristics of the peaking gap switch with different gapdistances and different pressures are presented and compared.When the working gas pressure is250kPa, the impulse breakdown voltage of the mainswitch is95.5kV with the rise time of27.2ns. The output impulse of the triggering systemwith peak value of more than120kV and rise time of less than44.8ns can trigger the two-electrode graphite spark gap switch reliably.